Seal assembly for rotary engines

ABSTRACT

A seal assembly for maintaining sliding sealing engagement between the body and vanes of a rotor and the side and end walls of the rotor chamber in a rotary engine. The body of the rotor is sealed to the flat end walls of the chamber by rings recessed into the end walls and spring pressed against the rotor. The rotor vanes have grooves running in their radial direction. The grooves are in the shape of a partial cylinder segment of more than one hundred and eighty degrees. Seals of similar shape are disposed in the grooves and run under the body seal rings. The vane seals have lips extending beyond the surfaces of the vanes and engaging the chamber walls. The vane seals are rotatable about their own axes in the grooves, and are spring pressed to rotate them in a direction to compensate for wear on the lips.

United States Patent 1191 Upchurch 1 SEAL ASSEMBLY FOR ROTARY ENGINES 14 1 Feb. 11, 1975 Primary Examiner-Samuel B. Rothberg Assistant Examiner-Robert I. Smith [76] Inventor: Lewis E. Upchurch, 31 Reservoir Ave., Revere, Mass. 02151 221 Filed: July 30, 1973 [571 ABSTRACT A seal assembly for maintaining sliding sealing engage- .N 7 [211 0 383 6 5 ment between the body and vanes of a rotor and the side and end walls of the rotor chamber in a rotary en- 1 277/8l P gine. The body of the rotor is sealed to the flat end [51] Int. Cl F0112 19/02, F03C 3/00 walls of the chamber by rings recessed into the end [58] Field of Search /8 walls and spring pressed against the rotor. The rotor 418/9, 13 1 260-267 vanes have grooves running in their radial direction. The grooves are in the shape of a partial cylinder seg- [56] fe e c Clled ment of more than one hundred and eighty degrees. UNITED STATES PATENTS Seals of similar shape are disposed in the grooves and 851,944 4/1907 Kray 418/121 f the body Seal rings- The Vane Seals have "P 1,601,397 9/1926 Kochendarfer 418/266 extendmg beyond the Surfaces of the vanes and engag- 2,391,360 12/1945 Stephens 418/266 ing the chamber walls. The vane seals are rotatable 3,200,752 8/1965 Clark et a1. 418/266 about their own axes in the grooves, and are spring 3,397,618 8/1968 Jensen 418/266 pressed to rgtate them in a direction to compensate UpChurCh for wear on the lips 3,711,229 l/l973 Kurio 418/121 8 Claims, 5 Drawing Figures 27C 1 l l I 1 1111111 I 1 1 4 A I I SEAL ASSEMBLY FOR ROTARY ENGINES This invention relates to seals for maintaining air tight sliding engagement between the body and vanes of an engine rotor and the walls of the rotor chamber in a rotary engine, and is particularly adapted for use in a rotary engine such as that described in my previous U.S. Pat. No. 3,413,962, dated Dec. 3, 1968.

BACKGROUND OF THE INVENTION An engine of the type described in my aforesaid patent has a rotor disposed in a cylindrical rotor chamber. The rotor carries at least one radially projecting vane which sweeps the walls of the chamber. A rotary gate rotating around an axis perpendicular to the rotor axis projects into the chamber and engages the side wall of the rotor. The gate has a slot which enters the chamber at the proper time to allow the vane to pass through. The chamber housing is provided with appropriate ports for intake of fuel, transfer of compressed mixture, and exhaust. The vanes and gates divide the space around the rotor into sections in which the various phases of the opersting cycle, intake, compression, combustion and exhaust take place. To keep these sections isolated from one another it is necessary to maintain an air tight sliding seal between the rotor body and the end walls of the chamber, and between the vanes and the end and side walls of the chamber.

One of the problems in this type of sealing is to compensate for wear on the seals. Another problem with respect to the vane seals is that while a vane is passing over ports or through the slot in a gate, the seals or per tions of them are not restrained by the walls of the chamber. The principal object of this invention is to provide a seal assembly which automatically compensates for wear on the sealing surfaces. Another object is to provide a vane seal assembly is mechanically keyed to the vane in such a way that the seal is restrained in the radial and axial directions of the rotor. Other objects, advantages, and novel features will be apparent from the following description.

SUMMARY In the assembly here disclosed, the sealing for the rotor body is provided by a pair of rings set in recesses in the housing and spring-pressed against the rotor. Each vane has grooves in its end faces, that is, the faces which engage the flat end walls of the cylindrical rotor chamber. These grooves are shaped in cross-section as a segment of a cylinder larger than one hundred and eighty degrees. Similarly shaped seal strips are mounted in the grooves, so that the outer edges of the grooves overhang portions of the seal strips and retain them in the axial direction of the rotor. The seals have partial collars received in recesses in the rotor to restrain the seals in the radial direction of the rotor. Each seal has a lip portion which is offset from the center of the seal and projects beyond the end face of the vane to engage the end wall of the chamber. On the opposite side of the seal center, a spring bearing on the collar tends to rotate the seal strip around its own axis in the groove and compensate for wear on the lip. The collar is disposed obliquely with respect to the axis of the seal strip so that rotation of the seal in its groove alos advances the strip in the radial direction of the rotor to compensate for wear on the tip which engages the cylindrical side wall of the chamber.

DESCRIPTION OF THE DRAWINGS In the drawings illustrating the invention;

FIG. 1 is a fragmentary cross-section in the region of the rotor chamber and rotor of an engine of the type to which a seal assembly constructed according to the in vention is adapted;

FIG. 2 is a side view ofa vane equipped with the vane seal assembly, somewhat enlarged;

FIG. 3 is an end view of a rotor vane equipped with the vane seal;

FIG. 4 is a fragmentary cross-section, somewhat enlarged, taken along line 4--4 of FIG. 3; and

FIG. 5 is and enlarged fragmentary cross-section taken in the region of the junction of the rotor body and vane seals.

DESCRIPTION OF THE PREFERRED EMBODIMENT In a rotary engine of the type partially illustrated in FIG. 1, the housing encloses a cylindrical rotor chamber 11 in which the rotor 12 is mounted. A pair of rotary gates 13 and 14 project into the rotor chamber. The gates are in the form of disks, and the rotor has a side wall of convex configuration, with which the gates are in sliding engagement. The gates are driven about axes perpendicular to the drive shaft 15 of the rotor. The rotor carries vanes 16 and 17 which sweep the walls of the chamber. The gates are provided with slots (not shown) which enter the chamber at the appropriate time to allow the vanes to pass through. Disposed in the housing and bearing against the flat end faces of the rotor 12 are seal ring assemblies 18 and 19. Seal assemblies 20 and 21 are disposed along the end faces of the vanes.

A typical seal assembly for a vane, for example vane 17, is shown in detail in FIGS. 2, 3, and 4. The tip face 17a of the vane sweeps the cylindrical side wall 11a of the rotor chamber. A rectangular strip 22 of seal material is disposed in a groove 23 running along the tip face and is backed up by a spring 24 which presses the strip into engagement with wall 11a.

Disposed along the end faces 17b and 17c of the vane, which sweep end walls 11b and 11c, respectively, of the rotor chamber, are grooves 25 and 26. These grooves have the cross sectional shape of a segment of a cylinder of somewhat more than 180. Sealing strips 27 and 28, likewise in the shape of a segment of a cylinder of somewhat more than 18O" a re disposed in grooves 25 and 26. The outer edges of the grooves overhang strips 27 and 28 and prevent their displacement in the axial direction of the rotor. Strips 27 and 28 carry partial collars 29 and 30 which are disposed obliquely with respect to the axes of the strips and received in similarly disposed recesses 31 and 32 in the rotor body.

Seal strips 27 and 28 have lip portions or flats 27a and 28a which projects beyond the grooves and engage walls 11b and 110, respectively, of the rotor chamber. The tips 27b and 28b of the strips extend beyond the tip face 17a of the vane and engage the side wall 11a of the rotor chamber. As shown in FIG. 4, a spring 33, secured to the rotor by a washer 34 and screw 35 recessed into the rotor body, bears on one end face 29a of collar 29. The spring tends to rotate strip 27 about its axis and hold lip 27a in engagement with wall 11a as the lip wears. Because of the oblique disposition of collar 29 and recess 31, rotation of the strip also advances the strip outward in the radial direction of the rotor and compensates for wear on the tip 27b. It is understood that the assembly including strip 28 is similar in all respects.

To facilitate assembly of the seal, the dimension A between the ends of the collar is less than the width B of the top of the groove. The strip is turned upside down and slid into the groove endwise, then rotated into its final position when the collar is lined up with recess 31.

One of the rotor body seals, generally indicated by the numeral 18, is illustrated in FIG. at its junction with the vane seal. The assembly is illustrated as it would appear after the seals have been run in. The clearance between the rotor 12 and the housing is exaggerated for clarity. A seal ring 36 disposed in an annular recess 37 in the housing 10 bears partly on the inner portion of strip 27 and partly on the end face 12a of the rotor body. A spring washer 38 bears on ring 36 and keeps it in engagement with face 12a and strip 27. A seal ring 39 disposed in a circumferential groove 40 in ring 36 seals the latter to the housing at one side. Ring 36 has an oblique surface 36a around its outer rim. As the engine is run in, ring 36 wears down the portion of lip 27 which it engages, and surface 36a cuts a mating oblique surface 27c in strip 27 As the strip rotates in its groove to compensate for wear on lip 27a, the strip as a whole moves outward in the direction of arrow 41 and the portion of the strip in contact with ring 36 moves upward in the direction of arrow 42, so that ring 36 cuts deeper into the strip. The angle of surface 36a is larger than the helix angle of travel of strip 27, so that surfaces 36a and 27c maintain contact with each other and prevent leakage across the vane at that point.

The rotor body seals prevent leakage across the middle of the rotor and the vane assemblies prevent leakage across the vanes, thus isolating the sections A, B, C, and D from one another.

What is claimed is:

l. A seal assembly, for sealing a first engine member to a second engine member while permitting relative sliding between the members, comprising: a groove and a recess communicating with said groove in said first member; a strip of seal material disposed in said groove, said groove and said strip having the crosssectional shape of a segment of a cylinder and having common axes, said strip having a collar disposed in said recess and limiting axial travel of the strip, and said strip being rotatable about its axis in said groove and having a sealing face disposed to one side of its axis and engaging said second member; and a spring secured to said first member and bearing on said collar on the other side of the strip axis and urging said face into engagement with said second member.

2. A seal assembly as described in claim 1, both said groove and said strip having the cross-sectional shape of a segment of a cylinder of more than 3. A seal assembly as described in claim 1, both said recess and said collar being disposed obliquely with respect to said axes and causing the strip to advance axially as it rotates.

4. A seal assembly as described in claim 1, said collar having the shape of a segment of a cylinder of less than 180.

5. A seal assembly, for an engine housing enclosing a rotor chamber having a cylindrical side wall and flat end wall and a rotor having flat end faces opposed to said end walls and a sidewardly projecting vane sweeping said side wall and a portion of said end walls, comprising: an annular recess in one of said end walls; a ring of sealing material disposed in said recess and engaging the adjacent end face of said rotor; a spring disposed in said recess and urging said ring into engagement with said adjacent end face; a groove extending along said vane and partially underlying said ring; a strip of sealing material disposed in said groove, said groove and said strip having the cross-sectional shape of a segment of a cylinder and having common axes, and said strip being rotatable about its axis in said groove and having a sealing face disposed to one side of its axis and engaging the end wall in which said annular recess is disposed; and a second spring bearing on said strip on the other side of its axis and urging said sealing face into engagement with said last named end wall.

6. A sea] assembly as described in claim 5 including a second recess disposed in said rotor, said strip having a collar disposed in said second recess,'said collar and said second recess being disposed obliquely with respect to said axes in such a way that rotation of said strip in said groove advances said strip toward said side wall, said strip having a tip portion engaging said side wall, and said ring having an oblique surface abutting said strip and adapted to wear a mating oblique surface in said strip as said strip rotates.

7. A sea] assembly as described in claim 5 including means for sealing said ring to said housing.

8. A seal assembly, in an engine having a housing enclosing a rotor chamber with a cylindrical side wall and flat end walls and a rotor disposed in said chamber and carrying a vane which sweeps said end walls, comprising: a groove along said vane; a strip of seal material disposed in said groove, said groove and said strip having the cross-sectional shape of a segment of a cylinder and having common axes, and said strip being rotatable about its axis in said groove and having a sealing face disposed to one side of its axis and engaging one of said end walls, said strip also having a tip portion projecting beyond said vane and engaging said side-wall; and a spring bearing on saidstrip on the other side of its axis and pressing said face toward the end wall it engages. 

1. A seal assembly, for sealing a first engine member to a second engine member while permitting relative sliding between the members, comprising: a groove and a recess communicating with said groove in said first member; a strip of seal material disposed in said groove, said groove and said strip having the cross-sectional shape of a segment of a cylinder and having common axes, said strip having a collar disposed in said recess and limiting axial travel of the strip, and said strip being rotatable about its axis in said groove and having a sealing face disposed to one side of its axis and engaging said second member; and a spring secured to said first member and bearing on said collar on the other side of the strip axis and urging said face into engagement with said second member.
 2. A seal assembly as described in claim 1, both said groove and said strip having the cross-sectional shape of a segment of a cylinder of more than 180*. .
 3. A seal assembly as described in claim 1, both said recess and said collar being disposed obliquely with respect to said axes and causing the strip to advance axially as it rotates.
 4. A seal assembly as described in claim 1, said collar having the shape of a segment of a cylinder of less than 180* .
 5. A seal assembly, for an engine housing enclosing a rotor chamber having a cylindrical side wall and flat end wall and a rotor having flat end faces opposed to said end walls and a sidewardly projecting vane sweeping said side wall and a portion of said end walls, comprising: an annular recess in one of said end walls; a ring of sealing material disposed in said recess and engaging the adjacent end face of said rotor; a spring disposed in said recess and urging said Ring into engagement with said adjacent end face; a groove extending along said vane and partially underlying said ring; a strip of sealing material disposed in said groove, said groove and said strip having the cross-sectional shape of a segment of a cylinder and having common axes, and said strip being rotatable about its axis in said groove and having a sealing face disposed to one side of its axis and engaging the end wall in which said annular recess is disposed; and a second spring bearing on said strip on the other side of its axis and urging said sealing face into engagement with said last named end wall.
 6. A seal assembly as described in claim 5 including a second recess disposed in said rotor, said strip having a collar disposed in said second recess, said collar and said second recess being disposed obliquely with respect to said axes in such a way that rotation of said strip in said groove advances said strip toward said side wall, said strip having a tip portion engaging said side wall, and said ring having an oblique surface abutting said strip and adapted to wear a mating oblique surface in said strip as said strip rotates.
 7. A seal assembly as described in claim 5 including means for sealing said ring to said housing.
 8. A seal assembly, in an engine having a housing enclosing a rotor chamber with a cylindrical side wall and flat end walls and a rotor disposed in said chamber and carrying a vane which sweeps said end walls, comprising: a groove along said vane; a strip of seal material disposed in said groove, said groove and said strip having the cross-sectional shape of a segment of a cylinder and having common axes, and said strip being rotatable about its axis in said groove and having a sealing face disposed to one side of its axis and engaging one of said end walls, said strip also having a tip portion projecting beyond said vane and engaging said side wall; and a spring bearing on said strip on the other side of its axis and pressing said face toward the end wall it engages. 